0411 swap + boost?

[The_Family_Tahoe]

Could use your help.

Long story short I want to boost the 1999 L31 Tahoe and use it as a daily driver. I need feedback on the best way to manage efi under boost. I see a lot of customization to the efi tune is possible with a 0411 swap and this allows for use of the original gauge cluster and transmission control in the 1999 model obs.
First question:
For a daily driven 1999 obs what is the best boosted engine control option for me, with no tuning experience:
1. The 0411 swap with hp tuners
2. A more automated learning controller like:
a. the edelbrock proflo piggybacking on the 0411 for transmission control
b. Holley terminator x max with transmission control, but how do I keep factory gauges?
c. Is there another method to control boosted L31 with efi?

I want big low end torque and driveability over top end hp. I'm visualizing 600 lbs of torque and less than 700 hp flywheel hp. Given these power numbers I don't think the L31 factory equipped intake manifold injection is sufficient. I have learned the fuel injection spider is problematic and doesn't lend itself to boost because fuel flow is not easily increased without the purchase of an expensive high flow spider. Given this limitation inherent to the factory injection, if this limitation is correct, what intake manifold type would you recommend that uses more common high impedance fuel injectors?

Additional context:
a. Need to keep factory climate control
b. Camshaft will be less than 216 intake duration, likely 205 or 212
c. Would rather not give up cruise control, and willing to consider aftermarket options
d. 76 mile daily commute and the idea of boosted small block cruise mpg is desired over a big block with comparable power numbers. I already that with another vehicle and my fuel bill would be absolutely outrageous with this commute, so much so that I bought a used Acura for commuting before I found this Tahoe
e. Very likely swap to 4L80e after boost is added and bugs are worked out with efi management
f. I'm using an already sourced gt45 turbo and Martin turbo exhaust manifold, these costs are 6-years-sunk

 

[Erik the Awful]

A 700 hp daily driver? It can be done, but it doesn't sound like you have the experience to do it. There are very few who do. It's rare for a 700 hp vehicle to be streetable, and it's exceptionally rare for it to be reliable. A 450 hp daily driver is more realistic.

The upgrade Vortec spider isn't terribly expensive, especially compared to the mods you're talking about. If you're currently running a stock engine, I'd target 400-450 horsepower, which an upgraded spider can handle.

 

[The_Family_Tahoe]

Is it rare?
There are multiple rpo vehicles available today with 700hp that are both reliable and streetable. Dodge, Ford, and GM all offer new vehicles with more than 700hp.

I have a 600hp square body that's got cold AC, an automatic transmission, and power brakes. While it's not fuel injected or 700hp it is both reliable and streetable. It's also within 14 percent of the 700 hp target. The mileage leaves something to be desired, and that's why I want to build a boosted small block.

Your suggested 450hp can be done naturally aspirated with efi tuning. If I have to tune efi anyway why not add boost? Boost multiplies the naturally aspirated power output. 700 hp is equivalent to plus one atmospheres over a naturally aspirated 350 hp combination and on paper a 350 hp small block is a very mild combination.

I'm looking for a way to control fuel and timing under boost, keep the oe gauge cluster, and control the transmission.

 

[RDF1]

Could use your help.

Long story short I want to boost the 1999 L31 Tahoe and use it as a daily driver. I need feedback on the best way to manage efi under boost. I see a lot of customization to the efi tune is possible with a 0411 swap and this allows for use of the original gauge cluster and transmission control in the 1999 model obs.
First question:
For a daily driven 1999 obs what is the best boosted engine control option for me, with no tuning experience:
1. The 0411 swap with hp tuners (You already have the LS PCM, no point in not using it. Ive made over 1200hp with it on turbo LS engines. But you have to be on top of the programming. The higher the HP the more sensitive the tune up will be or you gernade your engine. And there is zero automatic fueling correction)

2. A more automated learning controller like:
a. the edelbrock proflo piggybacking on the 0411 for transmission control
b. Holley terminator x max with transmission control, but how do I keep factory gauges?( Terminator x max would be easier to learn and give you several more options for boost control and fuel octane switching. Automatic fueling correction and way easier to learn than tuning for boost with Factory PCM. For factory gauges to work just leave the LS pcm in, On the GMT800 trucks i only splut the Crank signal for the Tach to work and Split VSS for speedo to work. Add a 2nd CTS since you cant split that signal. Holley doesnt need oil pressure input so leave it like it is.)
c. Is there another method to control boosted L31 with efi?

I want big low end torque and driveability over top end hp. I'm visualizing 600 lbs of torque and less than 700 hp flywheel hp. Given these power numbers I don't think the L31 factory equipped intake manifold injection is sufficient. I have learned the fuel injection spider is problematic and doesn't lend itself to boost because fuel flow is not easily increased without the purchase of an expensive high flow spider. Given this limitation inherent to the factory injection, if this limitation is correct, what intake manifold type would you recommend that uses more common high impedance fuel injectors? (Something simlar to this would be my vote for port injection. Id rather see a Dual plane tho to make more low end power. https://www.summitracing.com/parts/hly-300-260)

Additional context:
a. Need to keep factory climate control (Nothing changes no matter if you use stock PCM or Holley)
b. Camshaft will be less than 216 intake duration, likely 205 or 212
c. Would rather not give up cruise control, and willing to consider aftermarket options (cruise control only needs a Speed Input to work)
d. 76 mile daily commute and the idea of boosted small block cruise mpg is desired over a big block with comparable power numbers. I already that with another vehicle and my fuel bill would be absolutely outrageous with this commute, so much so that I bought a used Acura for commuting before I found this Tahoe
e. Very likely swap to 4L80e after boost is added and bugs are worked out with efi management (I would do the 4l80 swap before trying to make power, a broken 4l60 isnt worth anything.)
f. I'm using an already sourced gt45 turbo and Martin turbo exhaust manifold, these costs are 6-years-sunk (What are the specs on the GT45 turbo?)

My text in red

 

[RDF1]

Is it rare?
There are multiple rpo vehicles available today with 700hp that are both reliable and streetable. Dodge, Ford, and GM all offer new vehicles with more than 700hp.

I have a 600hp square body that's got cold AC, an automatic transmission, and power brakes. While it's not fuel injected or 700hp it is both reliable and streetable. It's also within 14 percent of the 700 hp target. The mileage leaves something to be desired, and that's why I want to build a boosted small block.

Your suggested 450hp can be done naturally aspirated with efi tuning. If I have to tune efi anyway why not add boost? Boost multiplies the naturally aspirated power output. 700 hp is equivalent to plus one atmospheres over a naturally aspirated 350 hp combination and on paper a 350 hp small block is a very mild combination.

I'm looking for a way to control fuel and timing under boost, keep the oe gauge cluster, and control the transmission.

Those engines are designed around that HP Number. Not a 250hp engine trying to make almost triple the HP it was designed with.

 

[The_Family_Tahoe]

Thank you @RDF1
Follow-up question:
It looks like I would use the holley x max to control the engine and transmission and use the GM computer to run the abs and gauges. Is it possible to do this without any tuning to the gm computer or will I need to "turn off" portions of the computer to run both the Holley and GM computers? Is it as simple as just removing wires from the gm computer that won't be used to manage the engine and transmission?

 

[RDF1]

Id disable everything unneeded in the PCM. It is used for the ABS but its not a big deal to leave the PCM on the side and unpin everything un needed and then disable everything in the tune.
The last 2002 silverado i did with a Holley it only had about 8 or so wires in the PCM left.

 

[Supercharged111]

I want to say I've seen the 500 number touted as a safe max hp range for the L31, but I don't recall if that was NA, boosted, crank, or wheel hp. He'll even a GenIII LS gets iffy north of 600 wheel with stock internals.

 

[RDF1]

Yea early Gen3s with the little rods arent good for anything over 600. Have to go for 2005+ LS to get them good factory racing rods.

 

[Erik the Awful]

Is it rare?
There are multiple rpo vehicles available today with 700hp that are both reliable and streetable. Dodge, Ford, and GM all offer new vehicles with more than 700hp.

Yes, it's rare. Buying a car designed with 700 hp is a far cry from trying to get 700 hp out of a thirty-year-old truck that came with 255 hp.

I have a 600hp square body that's got cold AC, an automatic transmission, and power brakes. While it's not fuel injected or 700hp it is both reliable and streetable. It's also within 14 percent of the 700 hp target. The mileage leaves something to be desired, and that's why I want to build a boosted small block.

Apologies, you might be the person to get it done. I take it you're a carburetor guy, and that's why you were asking about tuning? That said, streetable is not the same as "daily driver reliable", not by any stretch. I was recommending 450 hp because that's entirely doable for a daily driver.

Your suggested 450hp can be done naturally aspirated with efi tuning. If I have to tune efi anyway why not add boost? Boost multiplies the naturally aspirated power output. 700 hp is equivalent to plus one atmospheres over a naturally aspirated 350 hp combination and on paper a 350 hp small block is a very mild combination.

You're probably aware that the stock block is not going to make much more than 500 hp without some bottom end upgrades. It's highly unlikely your Tahoe came with 4-bolt mains, but that's probably better because at that power level you're going to want splayed bolts and a girdle.

Since you're going that far in, I personally would go with a Terminator X Max. From what I hear they're easier to work with. For the intake manifold, have you considered a traditional squarebore manifold with a throttle body?